It is striking to me that the manifesto author repeatedly lists race alongside gender when listing programs and preferences he thinks should be done away with, but, unlike gender, he never purports to have any scientific backing for this. The omission is telling. Would defenders of the memo still be comfortable if the author had casually summarized race and IQ studies to argue that purported biological differences — not discrimination or unequal access to education — explained Google’s shortage of African-American programmers?